[petsc-dev] various dot products messed up for complex numbers?

[Jed Brown]

Where is the update to every KSP (at least the CGs, but I think all of
them) to change the order? I don't see it in the repository. Note that this
notation is different from that used by most textbook and paper
descriptions of the methods.

On Apr 17, 2012 7:09 PM, "Barry Smith" <bsmith at mcs.anl.gov> wrote:
>>
>>
>>   Since PETSc was written and always implemented with mathematician
style* inner products, I have decided to keep it that way and call the
BLASdot_() with the arguments reversed. Note that until Matt added the
support for zdotc() we never called the BLAS for complex inner products and
thus never used the engineers style inner products.
>>
>>    Please report any problems,
>>
>>    Barry
>>
>> * please do not be upset by my joking reference to mathematician and
engineering style inner products.
>>
>>
>> On Apr 15, 2012, at 1:09 PM, Jed Brown wrote:
>>
>> > On Sun, Apr 15, 2012 at 12:55, Barry Smith <bsmith at mcs.anl.gov> wrote:
>> >   Real mathematicians conjugate the second one :-)
>> >
>> > I never unrderstood that choice. I like vectors to be column vectors,
one forms to be row vectors, and operations to have standard fixity. How
some mathematicians ended up with infix operators and postfix inner
products is beyond me.
>> >
>> >
>> >   The code to check is PETSc's conjugate gradient, there the conjugate
does mater :-).
>> >
>> > Looks right to me.
>> >
>> >        ierr = KSP_MatMult(ksp,Amat,P,W);CHKERRQ(ierr);          /*
w <- Ap         */
>> >        ierr = VecXDot(P,W,&dpi);CHKERRQ(ierr);                  /*
dpi <- p'w     */
>> >
>>
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